[Elranatamab treatment in a refractory multiple myeloma patient on maintenance hemodialysis]

A 68-year-old man was diagnosed with multiple myeloma complicated by acute renal injury due to cast nephropathy in August 2018. Although induction therapy with bortezomib and dexamethasone achieved a hematological response, he remained dependent on hemodialysis. Extramedullary lesions developed in April 2024 during fifth-line treatment with daratumumab, pomalidomide, and dexamethasone. In July 2024, elranatamab was initiated on non-dialysis days with standard premedication and without dose adjustment. Elranatamab was well tolerated, with adverse effects limited to grade 1 cytokine release syndrome during the first cycle, and no immune-effector cell-associated neurotoxicity syndrome. PET/CT after 4 cycles demonstrated extramedullary mass regression. Elranatamab was continued through 8 cycles without significant adverse events, with sustained clinical response. Although data on bispecific antibodies in patients on hemodialysis are limited, our case demonstrates that elranatamab can be administered safely and effectively in this population. Consequently, elranatamab could be a feasible and effective therapeutic option for patients with multiple myeloma on hemodialysis.